start() {@inheritdoc}

$this to(mixed $users) Set the recipients of the message.

mixed send(Mailable $mailable)

$this attachData(string $data, string $name, array $options = array()) Attach

string getKey() Get the API key being used by the transport.

HandleQueuedMessage class HandleQueuedMessage (

SendQueuedMailable class SendQueuedMailable (

start() {@inheritdoc}

SparkPostTransport class SparkPostTransport extends

send(Swift_Mime_Message $message, $failedRecipients = null) {@inheritdoc}